Little is known about the most effective therapy of progressive systemic RV dysfunction in these patients. Despite several recent studies demonstrating the benefit of beta-adrenergic blocking agents in improved left ventricular function in adults with heart failure and left ventricular dysfunction, there have been no reports of the use of beta-adrenergic blocking agents in adult patients with ventricular dysfunction due to congenital heart disease. This data collection study will be a single center, retrospective study; a chart review of patients with TGA (either DTGA or LTGA) and systemic right ventricular dysfunction.